Journal: Journal of Chronic Fatigue Syndrome. Volume: 13, Issue: 2/3, Cover Date: 2006 Authors: Leonard A Jason, David S. Bell, Kathy Row, Elke L. S. Van Hoof, Karen Jordan, Charles Lapp, Alan Gurwitt, Teruhisa Miike, Susan Torres-Harding, Kenny De Meirleir DOI: 10.1300/J092v13n02_01 [in prepress, abstract online] For a diagnosis of Chronic Fatigue Syndrome (CFS), most researchers use criteria that were developed by Fukuda et al. (1994), with modifications suggested by Reeves et al. (2003). However, this case definition was established for adults rather than children. A Canadian Case Definition (ME/CFS; Myalgic Encephalomyelitis/CFS) has recently been developed, with more specific inclusion criteria (Carruthers et al., 2003). Again, the primary aim of this case definition is to diagnose adult CFS. A significant problem in the literature is the lack of both a pediatric definition of ME/CFS and a reliable instrument to assess it. These deficiencies can lead to criterion variance problems resulting in studies labeling children with a wide variety of symptoms as having ME/CFS. Subsequently, comparisons between articles become more difficult, decreasing the possibility of conducting a meta-analysis. This article presents recommendations developed by the International Association of Chronic Fatigue Syndrome Pediatric Case Definition Working group for a ME/CFS pediatric case definition. It is hoped that this pediatric case definition will lead to more appropriate identification of children and adolescents with ME/CFS. Keywords: Pediatric CFS, definition, pediatric questionnaire